Carburetor



Patented Oct. 3, 1933 UNITED STATES PATENT OFFICE CARBURETOR Application August 7,

3 Claims.

The present invention relates broadly to the art of carburetion, and more particularly to improvements in carburetors of the type utilized for supplying a combustible mixture to an in- 5 ternal combustion engine.

Carburetors as usually constructed may be divided into three broad classes, these being the so-called down draft carburetor, the so-called up draft carburetor and the so-called horizontal carl buretor. The classes above referred to derive their designation from the general direction of air flow through the mixing chamber. In all carburetors, regardless of the class to which they belong, there are certain well recognized strucl tural elements whch are usually present. These include the mixing chamber, which, is ordinarily suitably attached to the engine manifold for supplying the combustible mixture thereto, the

air intake which supplies the air to the mixing chamber, a nozzle structure by means of which fuel is delivered to the mixing chamber, and a constant level chamber constituting the source of supply for the nozzle structure.

After a carburetor has been once installed on a given motor, it is seldom necessary to make any changes in either the mixing chamber or the air intake, although changes, adjustments, repairs and the like are frequently required either with respect to the float chamber or with respect to the nozzle structure. Inasmuch as the mixing chamber is usually provided with a throttle valve to which operating connections lead to a remote point, and the air intake is provided with a choker valve having similar connections, any

carburetor structure which necessitates removal either of the air intake or of the mixing chamber in order to permit access to the float chamber or to the nozzle structure, is open to objection.

The present invention has for one of its objects an improved carburetor construction adaptable to carburetors of each of the classes referred to as to its broad aspects, and facilitating the removal of the float chamber and nozzle structure independently of any of the other parts of the carburetor.

In the preferred embodiment of the invention, the construction is further such that the nozzle structure includes a more or less unitary member 0 which may be bodily removed from the float chamber, although normally carried by the oat chamber so as to be removable therewith.

The invention has for another of its objects the provision of a carburetor which by reason of its construction lends itself to compactness, thus 1931, Serial No. 555,693,

d in Belgium August 14, 1930 materially reducing the space required for the carburetor installation and effecting a corresponding reduction and saving in the metal required for its manufacture.

In the accompanying drawing I have shown for purposes of illustration only, certain preferred embodiments of the present invention. In the drawing: n

Figure 1 is a more or less diagrammatic view in vertical section of one form of carburetor constructed in accordance with the present invention;

Figure 2 is a detail sectional view along the line II--II of Figure 1;

Figure 3 is a diagrammatic view, partly broken away, illustrating the applicability of the invention to a horizontal carburetor; and

Figure 4 is an enlarged view of a portion of the mechanism shown in Figure 1.

.Referring more particularly to the drawing, there is illustrated a carburetor comprising a mixing chamber 2 in which is located the usual throttle valve 3. The mixing chamber is also shown as having therein a venturi 4 as is customary in the art. Cooperating with the mixing chamber is an air intake 5 provided with the usual choker valve 6 for restricting the air supply during starting or during periods when the motor is cold.

The air intake, constituting a separate unit, may be secured in any desired manner to the mixing chamber, and the mixing chamber in like manner may be provided with a flange 7 by means of which it may be secured to an engine manifold.

Laterally disposed with respect to the mixing chamber is a float chamber 8, the oat chamber being illustrated as provided with a substantially vertically extending face 9 and horizontally extending face 10. The plane of the face 9 is indicated by the chain line 9-9 and the plane of the face 10 by the chain line 10-l0. These two planes are disposed substantially at right angles one to the other, the plane 9-9 constituting a junction line between the float chamber and the mixing chamber, While the plane 10-10 constitutes a junction line between the oat chamber and an extension 11 formed on the mixing cham-V ber and serving as a cover for the float chamber.

Secured to the oat chamber so as to be removable therewith, and still removable there-A provided with a slot 14 through which the nozzle structure may project with the oat chamber in assembled relationship, the venturi 4 being provided with a similar slot 15. By reference to Figure 2, it will be noted that the float chamber is provided adjacent its horizontal surface 10 with inwardly projecting lugs 16 threaded to cooperate with screws 17 extending through the float chamber cover 11, and effective for maintaining the float chamber and nozzle structure in the position illustrated in Figure 1.

Formed within the float chamber is a boss18 constituting a pump cylinder, the walls of which have inlet openings 19 communicating with the interior of the float chamber. Movable within the cylinder is a hollow plunger 20 the lower end of which has any desired number and arrangement of fuel orifices 21. Surrounding the pump plunger and abutting at its lower end against the upper end of the boss 18, is a compression spring 22. This spring at its upper end engages a flange 23 on the plunger and therefore normally maintains the plunger in its elevated position of Figure l. In this position fuel may flow from the float chamber through the openings 19 and thence by way of openings 24 to the interior of the pump plunger. This fuel may then leave the pump plunger by wayy of the orices 21 communicating with a pump chamber 25. From this chamber there leads a channel 26 communicating by way of a calibrated opening 27 with a second channel 28. The fuel having entered the channel 28 is permitted to pass by way of a calibrated opening 29 into a channel 30 formed in the float chamber body. This channel alines with a channel 31 formed in the nozzle structure 12 and discharginginto a fuel and air nozzle 32.

For actuating the plunger there is provided a lever 33 having a pivotal mounting 34 in the float chamber cover l1, and bearing atits free end against the upper end of the plunger. When the lever is rotated in a clockwise direction as viewed in Figure 1, the plunger will be'moved downwardly against the action of the spring 22. This movement may be accomplished in any desired manner, but preferably by means of an operative connection of known type intermediate the lever and the throttle shaft, whereby the lever and throttle shaft always occupy correlated and predetermined positions. The `downward movement of the plunger -tends to trap fuel in the pump chamber 25, thus establishing a pressure condition which is effective for lifting a at valve 35 and sealing the orifices 21. The pressure is further eifective for moving downwardly a valve'36 against the action of a spring 37 and thus opening a port 38 communicating with the channel 28 before described.

Inasmuch as the port 38 has a greater capacity than the calibrated orifice 27,*there is thus rendered available an increased supply of fuel for accelerating purposes. As the throttle shaft is moved to its extreme open pomtion, the plunger 20 engages the valve 36 and unseats the same, thus holding the passage 38 open, and permitting an increased flow of fuel as required for the maximum throttle opening.

. air to the channel 42 and thus form an emulsion,

the nozzle structure is provided with a third chan- Lacasse' nel 43 communicating at its upper end through an opening 44 with the channel 42; communicating at its intermediate portion through an opening 45 with said channel, and communicating at its lower end with said channel through an opening 46. At its upper end the channel 43 communicates with' a passageway 47 alining with an opening 48 in the iioat chamber cover 11. This opening is therefore effective for continuously supplying from the air space of the carburetor, the desired supply of air for forming an emulsion within the channel 42. A portion of this air may also be delivered by way of channel 49 to port 50 intersecting the channel 31.

Fuel for idling purposes passes from channel 43 into a channel 51 formed in the float chamber body and communicating at its upper end to an idling nozzle 52 through a calibrated orifice 53. The fuel for idling is emulsified by air entering orifice 54 communicating with an annular groove 55 from which lead radial channels 56 to the interior of the fuel nozzle. Air may be supplied to the orifice 54 by way of a space 57 between the nozzle structure and the adjacent walls ofthe venturi and mixing chamber. This emulsion is delivered to a chamber 58 wherein it may be further emulsified by means of air passing from the air intake through a channel 59, annular space 60 and channel 61, which channel is controlled by a needle valve 62 of suitable construction. From the chamber 58 the mixture is conducted through a channel 63 to an idle opening 64 located in the main mixture passage adjacent the throttle 3.

As is customary in thev art, the desired fuel level within the float chamber may be maintained by the provision of a float 65 controlling a fuel inlet valve (not shown). The relationship of the parts is such that the fuel level is normally maintained substantiallly in the plane indicated in Figure 1.

From the foregoing description, it will be apparent that upon loosening the screws 17, the il'oat chamber 8 and the nozzle structure 12 may be bodily removed from their cooperative relation to the air intake and the mixing chamber without any necessity for disturbing the normal relationship or position of these parts. After removal, the nozzle structure 12 maybe removed if desired, depending upon the work to be done.

Removal of cap screw 66 permits ready access to the metering orifice 40, while removal of the screws 67 and 68 permits access respectively to the metering orifices 27 and 29. In like manner, removal of the plug 69 permits access to the valve 36. With the oat chamber removed, access is readily had to the pump plunger and to the idling nozzle 52. Thus all of the parts are rendered readily accessible without any necessity for disturbing the connections to either the choker valve or the throttle valve, or the operating connections between the throttle valve and the pump actuating lever. n

It will further be apparent that all of the channels which deliver emulsifled fuel to the mixing chamber, are located within the removable nozzle structure 12, with the exception of that passage required for the delivery of idling fuel. In like manner, all of the calibrated orifices for controlling the ow of the pure fuel are carried by the float chamber and removable therewith and readily accessible upon such removal. While it is desirable for obvious reasons to have the nozzle structure 12 formed in a piece removable as a unit from the iioat chamber, it will be apparent that the oat chamber and nozzle structure may comprise an integral body if desired. Thus the removal of the oat chamber effects removal of all parts of the carburetor requiring regulation or replacement, the only regulating means remaining on the fixed portion of the carburetor being the needle valve 62. In this manner the repair and replacement of the carburetor and carburetor parts is materially facilitated.

While Figure 1 illustrates the invention as applied to a down draft carburetor, it will be readily apparent that the invention is applicable in similar manner to an up draft carburetor with minor changes. For practical purposes it is sufficient to assume that the air travels in the opposite direction, reversal being made only in the mixing chamber, air intake and venturi as required for such an air flow.

In Figure 3 the invention is shown as applied to a horizontal carburetor, parts corresponding to parts already described being designated by the same reference characters having a prime aillxed thereto. From this figure it will be appment that the structure hereinbefore described lends itself admirably` to use in each of the three classes of carburetors before referred to.

Reference has heretofore been made to the compactness afforded by a construction of the character described herein. This greater compactness is attributable in large part to the fact that the nozzle structure occupies a space which would normally be devoted to the mixing chamber and the venturi. By forming these members with slots, and projecting the nozzle structure therethrough, many of the fuel feeding passages are located within what may be termed the wall space zone of the carburetor, thus making this space serve a double purpose.

While the foregoing description has been drawn to define the present invention as useful broadly in connection with carburetors of different types, it has been found to possess particular advantages when utilized with a down-draft carburetor such as illustrated, for example, in the drawing. With a down-draft carburetor as ordinarily utilized, the mixing chamber is customarily necessarily so positioned with respect to the exhaust manifold or some portion thereof, as to receive a very great quantity of heat therefrom. 'I'his heat, in carburetors of usual construction, is transmitted, by conduction, to the reservoir or float chamber, thus causing boiling of the fuel therein. In accordance withthe present invention, prejudicial boiling of this character is largely, if not entirelyfavoided by reason of the insulating joint "I0 separating the oat chamber from the mixing chamber, this joint being effective for largely diminishing the flow of heat transmitted from the mixing chamber tothe fuel reservoir.

From the foregoing description, taken in connection with the drawing forming a part hereof,

it will be apparent that there is provided a carburetor of improved constructional characteristics facilitating repair and renewal as may be required without Lthe necessity of removing or dismantling the entire carburetor. While certain preferred features of construction with respect to fuel delivery have been described, it will be understood that the invention is not limited thereto, and that changes in the construction and relationship of the parts may b e made without departing either from the spirit of the invention or the scope of my broader claims.

I claim:

1. In a carburetor for internal combustion engines,a mixing chamber adapted tobe secured to the engine, a float chamber cover projecting laterally from saidmixing chamber and providing a horizontal seating surface for a oat chamber, said mixing chamber providing a vertical seating surface for a float chamber, and`a float chamber detachably secured in position against said surfaces, said float chamber including a nozzle structure bodily removable therewith.

2. In a carburetor for internal combustion engines, a mixing chamber adapted to be secured to the engine, a float chamber cover projecting laterally from said mixing chamber and providing a horizontal seating surface for a float chamber, said ymixing chamber providing an opening and a vertical seating surface for a float chamber, and a float chamber detachably secured in position against said surfaces, said float chamber including a nozzle structure bodily removable therewith and substantially disposed within the wall space of said opening.

3. In a carburetor, a relatively fixed part having seating surfaces disposed in two planes intersecting each other to form substantially a right angle, and a removable part including a float chamber removably held in position against said seating surfaces, said float chamber having therein all of the calibrated passages for air or emulsion required for normal running conditions not including idling.

LOUIS LEON VIEL. 

